Capacitors and supercapacitors

Devices that store charge in an electric field: very fast and very long-lived.

Storage · Electrical and system · No. 92

• Storage
• Duration: Seconds to minutes

A supercapacitor can be charged a million times without wearing out, because nothing inside it ever changes chemically.

Chart: Illustration: Capacitors and supercapacitors

Where it comes from

Chart: Map of where it comes from

Charge sits physically as ions against porous carbon made mostly from coconut shells in Japan and South-East Asia, with no chemical reaction.

Three things to know

1. A Skeleton cell holds about 11.1 Wh/kg, against about 250 Wh/kg for a lithium-ion cell.
2. They lose charge fast, falling from full to half in about a month.
3. Materials make up 71% of manufacturing cost, and activated carbon must fall from USD 15/kg to below USD 10/kg.

The journey

1. 1 Coconut shellsMade into porous activated carbon
2. 2 ElectrodesHuge internal surface area
3. 3 ChargingIons line up against the carbon
4. 4 ReleasePower delivered in seconds
5. 5 UsesGrid inertia, trams, wind pitch control

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